A US woman who shot and killed her husband and two adult children before taking her own life is thought to have committed the shocking crime as a result of being ostracised from the religion she was raised in.

A federal judge sentenced a former Arkansas judge Wednesday to five years in prison — a stiffer punishment than prosecutors recommended — after he admitted giving young male defendants lighter sentences in return for personal benefits that included sexual favours.

Every time I tell a mate I’m doing a story on cryptocurrency, they invariably ask me the same two questions: should they invest their own hard-earned money, and which cryptocurrency will get them a Lamborghini/yacht/island quickest?

In a 60 Minutes online exclusive, reporter Liz Hayes quizzed Australian Prime Minister Malcolm Turnbull on his relationship with the unpredictable Twitter aficionado and US president Donald Trump ahead of their meeting at the White House Friday.

A man has been charged over the alleged derailment of a train that caused extensive damage in Melbourne last year, as well as further arson and sabotage-related offences.

The train derailed at a railway siding in Hurstbridge about 1.50am on November 1, Victoria Police said in a statement.

It crashed into carriages, fencing and security boxes and "caused extensive damage and disruption to the rail network," the statement read.

A 27-year-old man was arrested over the incident yesterday, after transit and arson investigators searched a Waterford Park home.

He has since been charged with more than 25 arson and sabotage-related offences, dating from 2009, police said.

Incidents related to the charges include a fire at the Newport fire museum in November 2009; a fire at the Newport steam rail club warehouse in March 2015; a fire at the Clonbinane CFA fire station in July 2015; a fire at the Tottenham railway signal hut on July 2015; a subsequent fire at the steam rail club warehouse in August 2015; four grass fires in Taradale and Malmsbury in December 2015; and a Mount Disappointment bushfire in December 2015.

Further related incidents this month include a grassfire in Kilmore east; a subsequent fire at the Tottenham railway signal hut; and a fire at a rubber matting specialist in Brooklyn.